There are numerous experimental and theoretical constraints on the
Higgs-flavon mixing angle \( \phi \) . These are discussed at length in,
e.g. refs. [1]}, [2]}, [3]} in the context of the
real singlet extension of the SM. We expect the constraints to be largely the
same in the \( B_3 - L_2 \)  model, as most constraints are independent of the
presence of the \( Z^\prime \)  and the extra degree of freedom from the
complexity of the flavon field.
Because the \( B_3 - L_2 \)  model is seen as a
low energy effective theory,
we disregard some theoretical constraints,
namely perturbative unitarity of scattering amplitudes in the high energy
limit and
the lack of Landau poles below the Planck scale [4]}.
In this work, we impose four constraints on the \( B_3 -L_2 \)  model: limits from direct Higgs searches at hadron colliders, the Higgs
signal strength measurements, agreement with the experimentally measured \( W \) 
boson mass and perturbativity of the Higgs-quartic couplings at the scale of
the
effective theory. These correspond to the four coloured regions in
figure REF .
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